The promo offer kicks off on July 1 and means that the wholesale cost of migrating punters onto unbundled lines from its own wholesale broadband products will fall 42 per cent from £34.86 to £20.00 (ex VAT).

The year-long offer seems generous on the surface but has one key string attached - it only applies to LLU operators migrating customers "in bulk per exchange".

Now, after some delay, BT has finally responded to our request to what constitutes a "bulk" order.

The answer...wait for it...is that the monster telco has yet to decide.

"We are currently negotiating with the industry," said a spokeswoman.

So, BT has announced a price promo that should bolster competition at the wholesale level but has left a key detail subject to negotiation.

If BT is able to say that the promo will begin on July 1 and represents a 42 per cent cut in price from £34.86 to £20.00 (ex VAT), why is it unable to lay out the criteria needed for LLU operators to be eligible for the discount? Or, as some within the industry believe, is this some stunt by BT?

If BT is really committed to LLU, as it says it is, why not just cut the cost for all LLU operators and make the discount permanent?